Once again, Zak had a really cool idea using a line graph.
I created a first version of this spreadsheet.
Then, this morning, I thought, "heck, computers are good at rolling numbers -- why not let them do the whole thing?"
I reformatted the spreadsheet and put in a random d10 and some hlookups. You fill out the Inputs table however you'd like and the Outputs table randomly fills with the data according to the random rolls.
Control-R recalculates the spreadsheet.
Here's a link if you want to get yourself a copy.